1. Field of the Invention
This invention relates to frames used to support a pack for carrying a load of material on the wearer's back. In particular, the invention relates to a maneuverable well balanced packframe for carrying heavy loads and is useful for backpacking, back country skiing and camping.
2. Description of the Prior Art
There are many known designs for external pack frames for supporting a pack bag and which comprise two vertical supports connected by transverse supports. In most of these pack frames the bag is positioned so that when carried it rests directly on the frame supports and the frame is attached to the wearer. Although these packframes have hip straps, a good deal of weight is supported by the shoulder straps. When the wearer leans forward, as is necessary in walking or skiing, the weight of the pack is taken off the hips and placed more upon the shoulders and lower back. This makes the pack difficult to carry and puts an extra burden on the wearer's back. The pack bag attached to the standard external frame also tends to flop around during vigorous activity, such as skiing or climbing.
U.S. Pat. No. 4,489,866 to Korte shows a rectangular packframe and pack bag. The bag is supported by the frame. The shoulder straps are attached directly to the frame. A vertical line drawn through the center of the pack bag is substantially parallel to the plane of the rectangular frame supporting structure. Once place upon the wearer's back, a substantial amount of the weight of the pack bag is placed upon the shoulder straps. This problem is typical of the disadvantages of conventional packframes and pack bags.
In U.S. Pat. No. 4,369,903 to Wilkes a packframe is shown which attempts to shift more of the weight of the load to the wearer's hips, thereby alleviating the load being supported by the shoulder straps. However, this packframe still has some of the same disadvantages of the prior art. The shoulder straps remain attached to the frame. Presumably the pack bag is mounted on the frame and the transfer of weight is accomplished with cross linkage bars extending from a crossbar on the upper portion of the frame to the hip straps. This patent does not teach nor suggest to suspend the pack bag from the frame so as to maintain the pack bag in a plane substantially diagonal to the plane of the frame.
In U.S. Pat. No. 3,734,366 to Wood the inventor is concerned with maintaining the pack bag away from the wearer's back. This is accomplished by the use of bowed flexible rods. However, since the shoulder straps remain attached to the frame, there is not a substantial shifting of the weight load to the hips nor is there a lessening of the weight supported by the shoulder straps.
In U.S. Pat. No. 204,066 to Merriam a knapsack is shown. This early knapsack is not supported by a packframe and the weight of the load is carried completely on the wearer's shoulders. More modern backpacks are shown in U.S. Pat. No. 4,420,103 to Douglas and 3,347,429 to Ruth. Neither of these patents teach the use of a packframe from which a pack bag is suspended diagonally in order to transfer more weight to the hips.